DOS/51
A serial DOS for a ROM-less 80C31 board (11.0592 MHz, 32K ROM, 2×32K RAM), running the real ROM image in an 8051 emulator in your browser at real-time speed over a 19200 baud console.
Quick start
help | list commands |
ls -l, cat hello.asm | look at the bundled examples |
asm -r primes.asm | assemble into upper RAM at 8000h and run |
nano hello.asm | full-screen editor (^O save, ^X exit) |
df, free, mem 8000 40 | RAM disk, memory and hex dump |
sdput hello.asm, sdls | copy a file to the SD card, list the card |
sdget NAME.EXT [file], sdrm NAME.EXT | copy a file from the card, delete it |
The board has an SD card on P1.4–P1.7 (SPI). Here it is a 16 MiB FAT16 card image kept in your browser (IndexedDB): Download card saves it as a disk image you can open on a PC, Insert card… loads a FAT16/FAT32 image from your computer. Card files use 8.3 names in the root directory.
Files live in the 24 KiB RAM disk in lower RAM (XDATA 2000h–7FFFh); programs, the assembler output and the editor buffer use the upper 32 KiB, which is mapped into both XDATA and CODE. This page keeps both RAM chips in your browser's local storage, so files survive a reload; Power cycle clears them. Nothing you type is sent anywhere.